Alterations of 5-HT1A, 5-HT1B and 5-HT2A levels have been linked to the development of anxiety, depression and psychiatric disorders such as schizophrenia [60,61,62,63,64,65,66,67,68,69,70], making these three types of receptor favorable targets for drug treatment. The gene discussed is HTR1A; the disease is depressive symptom measurement.